Access to private networks, by definition, may be difficult to establish from outside the private network. A private network may be a network that has a gateway, firewall, or has other mechanisms in place so that general users of the Internet may not be able to access hosts on the private network. An example of a private network may be an intranet used within a person's home, company, or other organization.
One technique for accessing a private network may be a Virtual Private Network (VPN) connection. In a VPN, a client may connect to the private network from outside the network and operate as if the client were connected inside the network. For example, once a VPN connection is established, any communication with the general Internet may be routed through a gateway on the private network and may be limited or restricted by the gateway.
Some VPN connections may be configured for split tunneling, where a client may be able to connect to a private network as well as connect to other Internet connections without going through the VPN connection. In some such situations, the private network may be exposed to various security vulnerabilities, and split tunneling is often discouraged.